Iraq's signature on Tuesday was an important milestone for the treaty, as it was one of the few remaining larger countries worldwide which have yet to sign the CTBT, the Vienna-based CTBTO said at a press release.

Tibor Toth, executive secretary of the Preparatory Commission for the CTBTO, said Iraq's signing of the Treaty was a "strong political signal for nuclear disarmament and non-proliferation."

"It will encourage other countries of the region and beyond to follow suit," he said.

So far a total of 179 states have signed the CTBT, which bans all nuclear explosions. A verification regime is being built to monitor compliance with the treaty. The 337 facilities under the International Monitoring System (IMS) are monitoring any sign of a nuclear explosion.